The present invention relates to an initial position setting method by which a V shape grind stone, a flat grind stone, a ditch excavation grind stone or a chamfering grind stone is set for an initial position of grinding work to perform a V shape grinding work, a flat grinding work, a ditch excavation grinding work or a chamfering grinding work of an outer periphery of a round edge in an eyeglass lens.
In a conventional lens grinding work method for an eyeglass lens, a circular reference lens used as a measurement standard is held by a pair of lens rotating shafts. Then a carriage is moved, for example by a manual operation, and the lens rotating shafts are moved downward (moved along X direction) from a predetermined position for the reference lens to be contacted with a grinding surface of a V shape grind stone or a flat grind stone. The moving distance in this case is measured by pulse numbers of a counter, and then a control of moving position of the lens rotating shafts, a setting of an original working position and the like are performed based on the pulse count numbers.
In this way, because the reference lens is manually contacted with a grinding surface of the V shape grind stone or the flat grind stone, the pulse count number of pulse motor which moves the carriage, can not be accurately measured, this makes the moving distance of carriage for every one pulse count incorrect, and the setting of the working original position of the V shape grind stone or the flat grind stone can not be accurately performed.
Furthermore, in the conventional lens grinding work apparatus, the ditch excavation grind stone and the chamfering grind stone are not composed in a structure by which they can be set accurately at the initial position for grinding work, for this reason a ditch excavation work and a chamfering work are performed with a rough estimation by an operator with reference to grinding state. This causes a problem that the ditch excavation work and the chamfering work are not accurately performed.
An object of the present invention is to provide an initial position setting method and a grinding work apparatus by which a V shape grind stone, a flat grind stone, a ditch excavation grind stone or a chamfering grind stone is set as an initial position of the grinding work apparatus.
To attain the above described object, this invention, according to claim 1, is characterized by an initial position setting method for grinding work apparatus comprising: a grind stone whose contour of cross section is circular; a pair of lens rotating shafts which are provided movably to approach and separate with reference to the grind stone along a normal line of the grind stone, which are rotatable and shiftable along an axial direction, and which hold a lens to be processed; a dedicated ditch excavation and chamfering grind stones which are provided rotatably and capable of moving to a predetermined position within a trace line of the lens rotating shafts; a driving means which makes the lens rotating shafts rotating, approaching and separating and shifting along the axial direction; and a driving and rotating means which makes the dedicated ditch excavation and chamfering grind stones moving to a predetermined position along the trace line and rotating; a measurement standard with a predetermined shape being held by the lens rotating shafts; the dedicating ditch excavation and chamfering grind stones being moved to a predetermined position within the trace line of the lens rotating shafts; the lens rotating shafts being moved along a normal line in order for the measurement standard to contact with a ditch excavation grind stone or a chamfering grind stones of the dedicating ditch excavation and chamfering grind stones; detecting the contact of the measurement standard with the ditch excavation grind stone or the chamfering grind stone by a contact detecting means; obtaining a moving distance of the lens rotating shafts when the contact detecting means detects the contact; and obtaining and setting an initial position of the lens rotating shafts on a basis of the moving distance and a dimension of the measurement standard.
In accordance with claim 2, an initial position setting method for grinding work apparatus is characterized by comprising: grind stones having a V shape grind stone and a flat grind stone whose contours of cross section are circular; lens rotating shafts which are provided movably to approach and separate with reference to the grind stone along a normal line of the grind stone, which are rotatable and shiftable along an axial direction, and which hold a lens to be processed; and a driving means which makes the lens rotating shafts rotating, approaching and separating and shifting along the axial direction; a measurement standard with a predetermined shape being held by the lens rotating shafts; the lens rotating shafts being moved along a normal line in order for the measurement standard to contact with the V shape grind stone or the flat grind stone; detecting the contact of the measurement standard with the V shape grind stone or the flat grind stone by a contact detecting means; obtaining a moving distance of the lens rotating shafts when the contact detecting means detects the contact; and obtaining and setting an initial position of the lens rotating shafts on a basis of the moving distance and a dimension of the measurement standard.
A grinding work apparatus for carrying out a method according to this invention may be characterized by comprising: a grind stone whose contour of cross section is circular; lens rotating shafts which are provided movably to approach and separate with reference to the grind stone along a normal line of the grind stone, which are rotatable and shiftable along an axial direction, and which hold a lens to be processed; ditch excavation and chamfering grind stones which are provided rotatably and are capable of moving to a predetermined position within a trace line of the lens rotating shafts; a driving means which makes the lens rotating shafts rotating, approaching and separating and shifting along the axial direction; and a driving and rotating means which makes the ditch excavation and chamfering grind stones move to a predetermined position along the trace line and rotate; the driving and rotating means moving the ditch excavation and chamfering grind stones to a predetermined position within the trace line of lens rotating shafts; the driving means moving the lens rotating shafts holding a measurement standard which has a predetermined shape along a normal line in order for the measurement standard to contact with a ditch excavation grind stone or a chamfering grind stone of the dedicating ditch excavation and chamfering grind stones after the driving and rotating means is operated; and the grinding work apparatus further including a contact detecting means to detect the contact of the measurement standard with the ditch excavation grind stone or the chamfering grind stone; a measuring means to obtain a moving distance of the lens rotating shafts when the contact detecting means detects the contact; and a setting means to obtain and to set an actual moving distance for one unit of measuring moving distance on a basis of the moving distance and a dimension of the measurement standard. Because a contact of the measurement standard with the ditch excavation grind stone or the chamfering grind stone is detected by the contact detecting means, and the moving distance of the lens rotating shafts is obtained when the contact detecting means detects the contact, the moving distance can be correctly obtained, and thus the initial position for the lens rotating shafts can be accurately set.
A grinding work apparatus for carrying out a method according to this invention may be characterized by including: grind stones having a V shape grind stone and a flat grind stone whose contours of cross section are circular; lens rotating shafts which are provided movably to approach and separate with reference to the grind stone along a normal line of the grind stone, which are rotatable and shiftable along an axial direction, and which hold a lens to be processed; and a driving means which makes the lens rotating shafts rotating, approaching, separating and shifting along the axial direction; the driving means moving the lens rotating shafts holding a measurement standard which has a predetermined shape along a normal line in order for the measurement standard to contact with the V shape grind stone or the flat grind stone; and the grinding work apparatus further including; a contact detecting means to detect the contact of the measurement standard with the V shape grind stone or the flat grind stone; a measuring means to obtain a moving distance of the lens rotating shafts when the contact detecting means detects the contact; and a setting means to obtain and to set an actual moving distance for one unit of measuring moving distance on a basis of the moving distance and a dimension of the measurement standard. Because a contact of the measurement standard with the V shape grind stone or the flat grind stone is detected by the contact detecting means, and the moving distance of the lens rotating shafts is obtained when the contact detecting means detects the contact, the moving distance can be correctly obtained, and thus the initial position for the lens rotating shafts can be accurately set.
Operation
In the present invention, claim 1, by the arrangement described above, because a contact of the measurement standard with the ditch excavation grind stone or the chamfering grind stone is detected by the contact detecting means, and obtaining the moving distance of the pair of lens rotating shafts when the contact detecting means detects the contact, the moving distance can be correctly obtained and thus the initial position for the lens rotating shafts can be accurately set.
In accordance with claim 2, because a contact of the measurement standard with the V shape grind stone or the flat grind stone is detected by the contact detecting means, and obtaining the moving distance of the lens rotating shafts when the contact detecting means detects the contact, the moving distance can be correctly obtained and thus the initial position for the lens rotating shafts can be accurately set.